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Methane Emissions of Beef Cattle Grazing Tall Fescue Pastures at Three Levels of Endophyte Infestation
Author(s) -
PavaoZuckerman Mitchell A.,
Waller John C.,
Ingle Teri,
Fribourg Henry A.
Publication year - 1999
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1999.00472425002800060036x
Subject(s) - grazing , festuca arundinacea , pasture , forage , agronomy , endophyte , trifolium repens , biology , rumen , beef cattle , cattle grazing , lolium perenne , neotyphodium , livestock , zoology , poaceae , fermentation , ecology , botany , food science
Methane (CH 4 ) is produced by fermentation in the rumen of cattle. Methane may play a part in global warming scenarios. Tall fescue ( Festuca arundinacea Schreb.) is an important forage in the eastern United States. The toxic syndrome associated with the endophytic fungus Neotyphodium coenophialum (E+) can be mitigated with management strategies that improve forage quality of E+ tall fescue pastures and animal performance. The sulfur hexafluoride (SF 6 ) tracer technique was used to determine the effects of tall rescue pasture management on CH 4 production in 1997–1998. Two steers ( Bos taurus ) on two pastures each of E+ tall fescue, of endophyte free (E−) tall fescue, of E+/E−(1:1 ratio), and of E+/ladino white clover ( Trifolium repens L.), and four steers and four lactating cows with nursing calves grazing either unimproved (UP) or best management practices (BMP) pastures were used to collect eructated CH 4 samples. Daily CH 4 emissions were about 95 to 200 g d −1 for steers and 150 to 240 g d −1 for cows. Steers grazing E+/clover pastures emitted 20% less CH 4 kg −1 d −1 than steers grazing E+, E−, or E+/E− in summer. Season and animal size were the major factors affecting CH 4 emissions. This first estimation of CH 4 emissions from free‐roaming cattle grazing tall fescue pastures indicates that (i) improved forage management strategies have little effect on daily emissions per animal that are primarily a function of rumen size and intake, and (ii) the amount of emission per unit of animal product is reduced when improved practices are implemented.